Since the beginning of the year, the power system has been using the management method of regular maintenance. With the increase of unit capacity and the development of science and technology, this type of maintenance management has become less and less able to meet the needs of modern production, and power plant management is transitioning to the state maintenance mode. State maintenance, also known as predictive maintenance (PDM), is a newly developed technology that combines multiple disciplines. It refers to the use of advanced instruments and equipment to monitor and diagnose the status of the unit in real time, according to the actual situation of the unit. Arrange maintenance items and time to make the inspection work targeted, reduce maintenance costs, reduce unplanned outage time, and extend equipment life. In 1986, the Monitoring and Diagnostic Center (MD) of the National Electric Power Research Institute (EPRI) was established in Philadelphia, USA. The center carried out state maintenance work at the Edison Power Plant, and used more than 40 monitoring and diagnostic technologies to evaluate and demonstrate the equipment status of the power plant. After a period of efforts, significant results were achieved. According to statistics, the steam turbine that had to be overhauled for 4 to 5 years has been extended to 6 to 8 years. The inspection time has been reduced from 8 weeks to 4 weeks. The equipment life is extended by 10% to 15%, and the operating capacity is increased by 10% to 30%. In the mid-1990s, China put forward the idea of ​​carrying out state maintenance in the power system, and carried out pilot projects in several domestic power plants, and achieved certain results. This paper combines the domestic and international power system steam turbine generator set and its auxiliary machine state maintenance work, discusses the status of state maintenance, puts forward some ideas of state maintenance work, and points out that the state maintenance work urgently needs to be solved several questions 1 steam turbine generator set Commonly used technology for state maintenance At present, most power plants are equipped with some instruments and equipment, which can monitor the status of the unit. Common methods include vibration analysis technology, oil analysis technology, acoustic emission technology, motor monitoring technology, valve monitoring technology, etc. . 1.1 Vibration Analysis Technology Vibration analysis is a relatively mature technology. Under normal circumstances, the damage of the equipment will be manifested in the vibration intensity, so by measuring the vibration changes of the equipment, you can have a general understanding of the unit status. 1.2 Oil Analysis Technology The oil analysis technology identifies machine failures based on changes in lubricant quality and the characteristics of the abrasive particles carried. Oil analysis includes tests on oil quality, oil contamination, and mechanical wear. The oil system includes a digital viscometer, a particle counter, a chromatographic analyzer, a microscope, and oil analysis software. The combination of oil analysis and vibration analysis will greatly improve the analysis and judgment. 1.3 Acoustic emission technology The high and low addition of thermal power generating units is the main pressure-bearing component of the power plant, which is prone to leakage and affects the economic operation of the unit. Since the high-addition and the hydrophobic cooler and the steam cooler are connected in series by a hydrophobic pipe or the like, when a leak occurs somewhere, it is difficult for the conventional method to detect the leak point in time. However, the application of acoustic emission technology can detect leaks in time. This is because the high and low tube bundles are prone to fatigue and corrosion to form cracks under high temperature and high pressure conditions. The grains inside the metal will be rearranged and slipped before the crack is cracked, and a weak acoustic emission signal will be generated. When the metal stress concentration of the pipe is maintained to a certain extent, the crack cracks and releases a large amount of strain from the domestic and international 5 open a repair work i test i-shaped Mshlg home t power plant lg to i widely used domestic face workers open bookmark8 can produce a lot Acoustic emission signal. Thereafter, the high-pressure fluid in the tube is sprayed outward from the crack to form a high-speed jet, and the high-speed fluid generates excitation and friction on the wall surface to generate acoustic emission sound waves. These elastic waves propagate along the metal surface, reflect and refract after encountering the interface, and finally propagate to the tube wall of the inlet and outlet water pipes. According to the presence or absence of the signal, the strength can be judged whether the leakage and the degree of leakage occur. Therefore, the application of acoustic emission technology can carry out real-time online monitoring of the high and low addition of the generator set, accurately determine the leakage location and leakage time, and provide a basis for the unit maintenance status maintenance. The parameters monitored by acoustic emission technology mainly include counting rate, signal amplitude and its distribution, spectrum and waveform. Acoustic emission technology can also be used for monitoring faults such as bearing wear and friction of moving parts. One of the key technical challenges that acoustic emission technology needs to solve is how to separate the acoustic emission signal from the ambient environmental noise. If this problem can be solved, the practicality of the acoustic emission technology will be greatly improved. 1.4 Motor monitoring technology is mainly used for spectrum analysis of motor current, flux and vibration, to diagnose rotor related problems and electrical faults. 1.5 Blade and rotor stress monitoring technology Blade failure is the primary cause of unplanned downtime of steam turbines. At present, foreign leaf life dynamic evaluation software can be used to evaluate the life of the blade. It calculates the static and dynamic stress and vibration characteristics of the blade, the material properties and the effects of the steam disturbance power based on the blade size data. The rotor stress and fracture assessment technique of the steam turbine generator set is based on the basic theories of thermoelastic stress and fracture mechanics, calculates the temperature and stress distribution of the rotor under different working conditions, guides the start-up and load-bearing process of the unit, and estimates the rotor life. 1.6 Valve monitoring technology The strain applied by the valve is measured by the strain gauge installed on the valve to monitor the wear and lubrication and other faults. Diagnose various problems with the valve by monitoring the characteristics of the motor current signal that drives the valve. 2 Turbine generator set state maintenance framework At present, although the power plant is equipped with a large number of instruments and equipment for unit condition monitoring, in general, these work are carried out relatively fragmented and do not form an organic whole. If these instruments and equipment can be organized, coordinate work in such a large mode of state maintenance, formulate corresponding specifications, and make full use of these data, it will greatly improve the use value of instruments and equipment. In the following, combined with the steam turbine generator set, some analysis of the state maintenance framework is made. 2.1 Develop a good state maintenance management mode A good management mode is the premise for the state maintenance work. From the perspective of power plants, state maintenance management can be divided into decision level, management, maintenance layer and team level 4. The decision-making level determines the maintenance project, the maintenance department, the inspection time, and the maintenance method. The management obtains the equipment status information, proposes maintenance according to the state detection technical standards and management system, formulates or reviews the maintenance plan, process, etc., and is responsible for the implementation supervision and acceptance of the work. The inspection layer accepts maintenance tasks and maintenance equipment, discovers and eliminates equipment defects, and formulates maintenance project implementation plans. The team masters the operation status of the equipment, reports to the higher level in time, and carries out maintenance and maintenance of the equipment according to the maintenance technical standards and process standards. Work must be highly valued by the power plant management department. Although high and fine equipment is the basis of state maintenance work, excellent technical personnel and good management system are the guarantee for the success of state maintenance work. State maintenance work must fully mobilize the enthusiasm of technical personnel at all levels, and mobilize the whole people to achieve good results. 2.2 Determining the status of maintenance and repair At present, there is still much controversy about whether the maintenance of the unit status should be carried out first or for the auxiliary machine. For example, the state maintenance work of auxiliary power plants in Japan has been carried out very well. Some data indicate that the power plant auxiliary machines have basically achieved state maintenance. At the same time, some power plants in Europe and America are starting from the mainframe. State maintenance requires huge investment in the early stage of the power plant, equipped with a large number of instruments and equipment, and the economic benefit of carrying out state maintenance work on the auxiliary machine is not as good as that of the main engine. However, on the other hand, there is a lack of mature experience in the state maintenance work on the mainframe, and there is a certain risk, and the risk of the auxiliary machine carrying out state maintenance is small. From the perspective of benefits and risks, both have their own advantages and disadvantages. Based on various factors, we believe that most of the domestic power plant auxiliary machines have backup machines, and the importance and benefits of the state maintenance work are relatively low. Therefore, the state maintenance work should be carried out first for the host. 2.3 Determining the equipment information to be collected by the state service The state maintenance system must include as much as possible the system information that can be obtained. We believe that the state overhaul system should include: 1) real-time operational data; (2) historical data; (3) inspection and inspection data; (4) equipment overhaul and missing data; (5) previous failure data; (6) The same type of unit; (7) technical supervision data and standards; (8) unit dynamics and thermodynamic model; (9) manufacturing and installation data. 2.4 Improve equipment inspection equipment inspection is a relatively complete equipment management method, is the lowest level of the state maintenance system, but also the basis of state maintenance work. Equipment inspection system refers to the careful inspection of equipment according to the preset period and method, so that hidden dangers of equipment can be discovered, prevented and dealt with at an early stage. It includes three levels of daily inspections by operators, regular professional inspections by inspection personnel, and precision inspections. The inspection personnel should do a good job of filling out the inspection log and equipment analysis report. On this basis, the results of the inspection are analyzed, the degree of deterioration of equipment components is mastered, and the fault repair is arranged in a timely manner. Combined with planned maintenance, equipment maintenance is effectively implemented, and equipment maintenance is changed from preventive maintenance to predictive maintenance. In order to effectively implement the point verification system, it is necessary to formulate more detailed specifications, such as: equipment inspection work management methods, equipment daily inspection work management regulations, point inspector post responsibility system, equipment division management method, equipment elimination management Measures and other related systems. 2.5 Development and Maintenance Management System There are many power plant equipments, and the amount of information involved in maintenance is very large. It is very necessary to have a computerized system to manage. The maintenance management system shall be able to record and manage equipment historical information, relevant maintenance information, formulate maintenance procedures, arrange maintenance tasks and personnel, conduct inspection and inspection of inspection quality, and do a good job in material management and maintenance cost accounting. The equipment maintenance management system is not only a simple process of collecting, sorting and inputting a large amount of data, but more importantly, it should be able to inspect the maintenance management method and establish an effective modern maintenance management system. The equipment overhaul management system is a set of basic tools for power plant maintenance management, and it is rarely exhibited. In order to carry out technical training and assessment for new workers, it is also possible to develop maintenance and simulation and training systems based on the above work. The system can be combined with the existing operational simulation training system of the power plant to form a more comprehensive power plant training system. 2. Establish a state maintenance workstation. The equipment status maintenance workstation is mainly used to receive a large amount of information from the condition monitoring system, comprehensively process the information, propose equipment status reports, development trends and maintenance suggestions, automatically generate unit status reports, and explain the conclusions made according to needs. . When technicians analyze the operating conditions of the unit, it is often necessary to combine multiple monitored parameters for analysis. For example, vibration, oil analysis, lubricating oil temperature, Wujin temperature, top shaft oil pressure and other parameters can be combined to analyze the bearing status. Therefore, the workstation must have certain intelligence, that is, it can automatically determine the relationship between the parameters, and accurately judge the state of the device from the height of the artificial intelligence. Of course, all the conclusions made by the workstation under the current situation still need to be verified by the technicians. The workstation can be placed in a power plant or at a diagnostic center where the relevant technicians can be gathered for analysis. 3 State maintenance urgently need to solve the task China's power system technology and management level distance to achieve unit state maintenance there is still a certain distance, but we should gradually improve and improve monitoring and diagnostic technology towards this goal, develop a state monitoring system in line with national conditions . Some of the problems that need to be solved urgently in the current state maintenance work include: improving the state maintenance management system. Such as power plant equipment inspection and inspection management system, power plant metal test management system, power plant technology supervision and management system, power plant thermal test management system and personnel management system at all levels. Determine the state maintenance technical specifications and standards, and establish a state maintenance work instruction on this basis. Research and development of information fusion technology. The state maintenance system contains a large amount of data. How to extract the characteristic information reflecting the state of the system from these data is directly related to the judgment of the state of the unit by the state maintenance system. Information fusion technology is a new type of technology that has developed rapidly in the past decade. Information fusion technology has great potential in the field of state maintenance, but at present there is still a long way to go from practical application, and people need to make great efforts to study. The intelligence of the conditional maintenance system. The status maintenance system is by no means a simple accumulation of data. The state maintenance system should be able to simulate the way people think to make judgments on the operating status of the unit. This requires the state-of-the-art maintenance system to incorporate artificial intelligence technology organically and improve the level of the state-of-the-art maintenance system. This work requires a close integration of state maintenance developers, technicians in power plant-related fields, artificial intelligence experts, and computer programmers. 4 Conclusions State maintenance has enormous economic potential. The implementation of state maintenance is not only to configure some monitoring equipment, but more importantly, to establish a corresponding maintenance management system to ensure the implementation of advanced maintenance strategies, in order to achieve all-round modern management of equipment operation and maintenance. The conditional maintenance system should have some intelligence. The status of the maintenance system is very large, and it is impossible to do it very well from the beginning. It should be continuously adjusted and improved according to the implementation effect and actual situation. (Continued from page 221) An anti-steam ring is installed on the exposed shaft section to block the leakage of steam from the steam seal into the bearing housing; and fourth, to strengthen the monitoring and adjustment during operation of the equipment. For example, the steam pressure supplied to the steam seal of the end of the steam turbine should be appropriate and meet the requirements of the regulations. The oil pressure on the oil side of the oil cooler must be greater than the water pressure on the water side to prevent water from entering the oil system due to damage of the tube bundle. When the steam turbine is under low load, the shaft sealing steam comes from the shaft sealing steam regulating station, and the steam source quality from the regulating station is automatically adjusted by the regulating valve. Therefore, the adjustment performance of the regulating valve is directly related to the work of the shaft sealing system. Managing and maintaining the shaft seal adjustment station is the key to solving the water inflow of the steam turbine at low load. This includes shaft sealing steam temperature, pressure regulating valve regulation performance, relief valve regulating performance and discharge capacity of the discharge pipe, adjustment control strategy, and variable load response rate. 3.2 Guarantee the quality of maintenance With the improvement of the operation level of the unit, the cycle of overhaul of the unit is getting longer and longer, and the quality of maintenance has more and more impact on the economy and safety of the unit. It is more important to grasp the quality of equipment maintenance. In the overhaul, it is necessary to strictly implement maintenance technical standards and improve the quality of maintenance. Improve the design of the tank negative pressure system and the bearing oil seal structure, and properly control the negative pressure of the unit oil system. After the fuel tank exhaust fan is overhauled, the system negative pressure should be measured. The system negative pressure should not be too high. The bearing oil seal should not leak oil, and it is generally controlled between. Equipment insulation work is often neglected in the maintenance of power plant equipment, but the quality of insulation is very important for the safe operation of equipment. The insulation at the shaft seal must be sufficiently spaced from the bearing to ensure that the steam is not drawn into the oil system by the negative pressure of the oil system due to the leakage of the shaft seal. The oil system is a very important system for steam turbine generators, just as the blood system is as important to humans. It is necessary to timely summarize and analyze various problems and accidents that occur in the operation of the oil system to prevent the same accident from happening again. The quality of oil service work and the quality of oil are directly related to the service life of oil system equipment for power systems, the safe operation of electricity production and economic benefits. Especially in recent years, with the commissioning of large-capacity and high-parameter units, higher requirements have been put forward for the oil work of the power system. The oil supervision and management institutions should be improved, and the management, supervision and maintenance of oil quality should be strengthened. . Shandong Buluoer Intelligent Technology Co., Ltd. has carved a remarkable niche in the market for manufacturing, wholesaling, importing, exporting and retailing a high-quality range of Welding Accessories. Offered products range consists of Plasma Cutting Machines, Manual Metal ARC Welding Transformers and Welding Machines. Our complete product range is manufactured under the supervision of trained personnel who use the utmost quality raw material. 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September 23, 2021